The use of touch-sensitive surfaces as input devices for computers and other electronic computing devices has increased significantly in recent years. Exemplary touch-sensitive surfaces include touch pads and touch screen displays. Such surfaces are widely used to interact with an electronic document on a display.
Exemplary interactions include navigating and editing an electronic document. For example, a user often needs to scroll or translate the electronic document to text that needs to be edited. The user also needs to position or reposition an insertion marker in the text to be edited and then input additional text (e.g., via a keyboard). These document navigation and editing operations are typically performed numerous times while working on an electronic document. These interactions may be performed in any application that includes text entry capabilities (e.g., a drawing application, a presentation application (e.g., Keynote from Apple Inc. of Cupertino, Calif.), a word processing application (e.g., Pages from Apple Inc. of Cupertino, Calif.), a website creation application (e.g., iWeb from Apple Inc. of Cupertino, Calif.), or a spreadsheet application (e.g., Numbers from Apple Inc. of Cupertino, Calif.)).
But existing methods for navigating and editing text via touch-sensitive surfaces are cumbersome and inefficient. For example, positioning an insertion marker by dragging the insertion marker in accordance with a finger being moved across a touch screen requires careful hand-eye coordination and a steady finger to correctly position the insertion marker at the desired location. In addition, the heuristics used to disambiguate whether a finger gesture is trying to reposition the insertion marker (without moving the document) or whether the finger gesture is trying to move the entire document (without repositioning the insertion marker) make repositioning the insertion marker a slow and tedious process, thereby frustrating users and wasting energy. This latter consideration is particularly important in battery-operated devices.